<script>
    // 不做为构造函数
    let Person = ()=>{

    }
    // new Person();  //TypeError: Person is not a constructor





    // 函数参数的默认值 （function,箭头函数）
    function setStyle(width="100px",height="100px"){
        console.log(width,height);
    }
    setStyle();


    let fn = (a=100,b=200)=>{
        console.log(a,b);
    }
    fn();
</script>